1. Field of the Invention
The present invention relates to a swivel joint mounted in the ceiling area of two hinge-linked vehicles.
2. Description of the Prior Art
A known procedure for connecting two hinge-linked vehicles, for example of an articulated bus or of a corresponding rail vehicle, is to provided an articulation thrust bearing that ensures the connection of the two vehicles in the bottom area. Such an articulation thrust bearing has three degrees of freedom. An articulated vehicle exclusively provided with such an articulation thrust bearing would be unstable due to the motivity of the vehicles relative to each other in all the three degrees of freedom. That is why a swivel joint has to be provided, said swivel joint being mounted in the ceiling area of the two vehicles and limiting the number of degrees of freedom in which the vehicles may move relative to each other. This clearly shows that it is this upper swivel joint that is stabilizing the two hinge-linked vehicles.
In order to ensure a perfect functioning of the hinge joint as a whole between the two vehicles, it is necessary to have the hinge points of the upper and of the lower swivel joint exactly aligned above each other. If this is not the case, the two vehicles are displaced relative to each other.